Math 7 · Unit 13: Probability · Cambridge Lower Secondary Maths Stage 7

Questions

1. 1. Question 1a: A card is taken without looking. Find the probability that the letter is X.

   • 3/5
   • 1/2
   • 2/5
   • 1/3
   Check

2. 2. Question 1b: A card is taken without looking. Find the probability that the letter is Y.

   • 2/5
   • 3/5
   • 2/3
   • 1/2
   Check

3. 3. Question 1c: A card is taken without looking. Find the probability that the letter is Z.

   • 1/3
   • 1
   • 0
   • 1/5
   Check

4. 4. Question 2a: Here is a spinner with seven equal sectors. Work out the probability that the spinner lands on 2.

   • 2/7
   • 1/6
   • 1/7
   • 1/2
   Check

5. 5. Question 2b: Here is a spinner with seven equal sectors. Work out the probability that the spinner lands on a number that is more than 2.

   • 4/7
   • 5/7
   • 2/7
   • 6/7
   Check

6. 6. Question 2c: Here is a spinner with seven equal sectors. Work out the probability that the spinner lands on an even number.

   • 4/7
   • 3/6
   • 1/2
   • 3/7
   Check

7. 7. Question 2d: Here is a spinner with seven equal sectors. Work out the probability that the spinner lands on an odd number.

   • 4/7
   • 1/2
   • 4/6
   • 3/7
   Check

8. 8. Question 2e: Here is a spinner with seven equal sectors. Work out the probability that the spinner lands on a number that is less than 10.

   • 1
   • 7/10
   • 9/7
   • 0
   Check

9. 9. Question 2f: Here is a spinner with seven equal sectors. Work out the probability that the spinner lands on a prime number.

   • 3/7
   • 4/7
   • 5/7
   • 2/7
   Check

10. 10. Question 3: Look at the spinner in Question 2. Which three outcomes are mutually exclusive and have different probabilities?

    • lands on an even number; lands on more than 2; lands on 7
    • lands on 1; lands on an even number; lands on 3
    • lands on 1; lands on 2 or 3; lands on 4, 5 or 6
    • lands on 1; lands on 2; lands on 3
    Check

11. 11. Question 4a: There are 10 balls in a bag: 4 red, 3 blue, 2 green and 1 yellow. A ball is taken without looking. Which gives the probabilities of blue, red, green, yellow and purple, in that order?

    • 3/10, 4/10, 2/10, 1/10, 1/10
    • 3/7, 4/6, 2/8, 1/9, 0
    • 3/10, 2/5, 1/5, 1/10, 0
    • 3/4, 2/4, 1/2, 1, 0
    Check

12. 12. Question 4b: 4 red, 3 blue, 2 green and 1 yellow ball. What is the probability that the ball taken is not red?

    • 3/5
    • 1/2
    • 2/5
    • 4/10
    Check

13. 13. Question 4c: the yellow ball is removed, leaving 4 red, 3 blue and 2 green. What is the probability now of taking each colour?

    • red 1/3, blue 1/3, green 1/3
    • red 4/9, blue 1/3, green 2/9
    • red 4/9, blue 3/10, green 2/9
    • red 4/10, blue 3/10, green 2/10
    Check

14. 14. Question 5a: Ushi throws a fair 6-sided dice. Which outcomes have probabilities 50%, 1/6, 5/6, 1/3 and 2/3, in that order?

    • an even number; a 1; not a 1; a 1 or a 2; a number less than 3
    • a number more than 3; a 1; not a 6; a 1, 2 or 3; a number more than 1
    • an even number; a 6; a 1; a 1 or a 2; a number less than 3
    • an even number; a 1; not a 6; a 1 or a 2; a number more than 2
    Check

15. 15. Question 5b: Ushi throws a fair 6-sided dice. Is it impossible to find an outcome with a probability of 25%?

    • Yes
    • No
    Check

16. 16. Question 6a: A teacher has a class of 20 students. How can the teacher choose one name at random?

    • Pick the first name on the register
    • Pick a girl
    • Put all 20 names in a bag and pick one without looking
    • Pick the tallest student
    Check

17. 17. Question 6b: a teacher has a class of 20 students. 12 are boys. One name is chosen at random. Find the probability that the student chosen is a girl.

    • 8/12
    • 3/5
    • 2/5
    • 1/2
    Check

18. 18. Question 7a: A counter is removed from a bag without looking. The probability that it is red is 60% and that it is blue is 30%. Must there be other colours in the bag?

    • Yes
    • No
    Check

19. 19. Question 7: the probability that a counter is red is 60% and that it is blue is 30%. What can you say about the probability that it is green?

    • It is at most 10%.
    • It is exactly 10%.
    • It is 90%.
    • It is 0%.
    Check

20. 20. Question 8a: a fair dice has 20 faces, numbered 1 to 20. Find the probability that the outcome is a multiple of 3.

    • 7/20
    • 3/10
    • 1/3
    • 1/4
    Check